Stacked LCD Unit with Inverted Scanning for Flicker Reduction
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Solution Overview
Problem
Stacked liquid crystal display (LCD) units face issues with low contrast ratio and noticeable flicker due to the inherent limitations of individual LCD panels, which affect image quality, especially when displaying dark or bright areas simultaneously.
Innovation Solution
The implementation of a stacked LCD unit design where multiple LC panels are aligned with opposite scanning directions to reduce flicker, and a mode switching mechanism that adjusts scanning directions based on whether the content is a still or moving picture to minimize image quality degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple LC panels are stacked to improve contrast ratio, then the contrast ratio is enhanced, but flicker becomes more noticeable
Solution Approach 1:
The patent applies inverse scanning by alternating the scanning directions of adjacent LC panels. While one panel scans from top to bottom, the adjacent panel scans from bottom to top. This inversion causes the potential changes in each panel to occur at different times, thereby reducing the noticeable flicker effect when multiple panels are stacked, while maintaining the improved contrast ratio.
Solution Approach 2:
The patent implements periodic scanning where each LC panel is scanned in an alternating sequence. By establishing a periodic scanning pattern where panels are scanned in opposite directions alternately, the system reduces flicker perception. The periodic action ensures that not all panels change their potential simultaneously, distributing the potential changes over time and reducing the cumulative flicker effect.
2Device complexity
If all LC panels are scanned in the same direction, then the scanning control is simple, but flicker intensity increases
Solution Approach 1:
The patent inverts the scanning direction of adjacent panels to reduce flicker. Instead of all panels scanning in the same direction (top to bottom), the patent makes alternating panels scan in opposite directions (top to bottom and bottom to top). This inversion strategy reduces the flicker intensity by preventing simultaneous potential changes across all panels, while the scanning control remains relatively simple through alternating direction control.
3Device complexity
If scanning direction is fixed for all panels, then the control mechanism is simple, but image quality degrades when displaying mixed luminance areas
Solution Approach 1:
The patent inverts the scanning direction of adjacent panels to improve image quality when displaying mixed luminance areas. By making alternating panels scan in opposite directions, the system reduces the impact of simultaneous potential changes, thereby maintaining better image quality and contrast ratio performance while keeping the control mechanism relatively simple through alternating direction control.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach significantly enhances the contrast ratio and reduces flicker intensity, providing improved image quality and comfort for observers by optimizing scanning directions based on content type.
Implementation Method 1
a first LC panel 133 and a second LC panel 136 stacked one on another... corresponding pixels of the LC panels overlapping each other... reducing the black luminance
Data Source
AI summary
A LCD unit includes a plurality of LC panels stacked one on another. If a picture to be displayed on the LCD unit is a still picture, one of the LC panels consecutively scans plurality of rows of pixels in a direction opposite to the scanning direction of the rows of pixels in the rest of LC panels. If the picture is a moving picture, all the LC panels consecutively scans in the same direction.